Control of corrosion and scale in circulating water systems by means of partial esters of polyfunctional organic acids

摘要

For inhibiting corrosion and scale on ferrous metal parts in a circulating water system there is added to the water in such system from 10 to 500 ppm of a partial ester of a polyfunctional acid having a free carboxylate, phosphonate or sulfonate group and another carboxyl group which is esterified with a polyoxyalkylated derivative of an alkyl, alkaryl, or alkenyl alcohol having a terminal hydrocarbon group of 8-20 carbon atoms. In some preferred embodiments there is added with the partial ester from 10 to 500 ppm of a dispersible oil which may also include a surface active agent for dispersing the oil in water. Preferred partial esters include partial esters of citric, malic, tartaric, maleic, adipic and phthalic acids partially esterified with an alkyl polyoxyethylene alcohol having 2 to 4 ethoxy groups.